From: Austin Ziegler <halostatue@...>
Date: 2011-06-04T10:14:01+09:00
Subject: [ruby-core:36729] Re: [Ruby 1.9 - Feature #4818][Open] Add method marshalable?

On Fri, Jun 3, 2011 at 1:44 PM, Joel VanderWerf
<joelvanderwerf@gmail.com> wrote:
> On 06/02/2011 07:07 PM, Joey Zhou wrote:
>> Some objects can not be marshaled. Maybe there should be a method to tell
>> it.
>>
>> hash = Hash.new {|h,k| k * 2}
>>
>> this hash can't be marshaled because it has a default proc. If existing
>> such method:
>> Marshal.marshalable?(hash) #=> �method "Marshal.marshalable?"
>> hash.marshalable? #=> �method "Kernel#marshalable?"
>
> What would it do in this case?
>
> hash = Hash.new {|h,k| k * 2}
> [hash].marshalable?
>
> So the method needs to recurse arbitrarily deep. So #marshalable will need
> to know just as much as Marshal.dump itself does about the object references
> contained in an object. Abstracting this out of Marshal.dump will be complex
> and will depend on external libraries and gems, which do custom dumping.
>
> Why not just marshal and rescue?

Or:

hash = Hash.new { |h, k| h[k] = k * 2 }
class << hash
  def marshal_dump
    Hash[*self.to_a]
end
hash.marshalable? # => true

-a
-- 
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